A080710 a(0) = 1; for n>0, a(n) is taken to be the smallest positive integer greater than a(n-1) which is consistent with the condition "n is a member of the sequence if and only if a(n) is a multiple of 3".

1, 3, 4, 6, 9, 10, 12, 13, 14, 15, 18, 19, 21, 24, 27, 30, 31, 32, 33, 36, 37, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 51, 54, 57, 58, 59, 60, 63, 64, 66, 69, 72, 75, 78, 81, 84, 87, 90, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 105, 108, 111, 112, 113, 114, 117, 118, 120

Offset

0,2

Comments

Is this the same sequence as A115837? - Andrew S. Plewe, May 08 2007

Links

Table of n, a(n) for n=0..66.

B. Cloitre, N. J. A. Sloane and M. J. Vandermast, Numerical analogues of Aronson's sequence, J. Integer Seqs., Vol. 6 (2003), #03.2.2.

B. Cloitre, N. J. A. Sloane and M. J. Vandermast, Numerical analogues of Aronson's sequence (math.NT/0305308)

Index entries for sequences of the a(a(n)) = 2n family

Formula

a(a(n)) = 3*(n+1).

Prog

(PARI) {a=1; m=[1]; for(n=1, 67, print1(a, ", "); a=a+1; if(m[1]==n, while(a%3>0, a++); m=if(length(m)==1, [], vecextract(m, "2.."))); m=concat(m, a))}

Crossrefs

Cf. A003605, A079253, A080711, A080712.

Cf. A079000, A003605, A079253, A080711, A080712.

Sequence in context: A190899 A173671 A325440 * A115837 A102342 A286692

Adjacent sequences: A080707 A080708 A080709 * A080711 A080712 A080713

Keyword

nonn,easy

Author

N. J. A. Sloane, Mar 05 2003

Extensions

More terms and PARI code from Klaus Brockhaus, Mar 06 2003

Status

approved